Question: $ A = \left[\begin{array}{rrr}1 & 2 & 2 \\ 2 & 0 & 1 \\ 2 & 2 & 0\end{array}\right]$ What is $ A^{-1}$ ?
$ = \left[\begin{array}{rrr}-\frac{1}{5} & \frac{2}{5} & \frac{1}{5} \\ \frac{1}{5} & -\frac{2}{5} & \frac{3}{10} \\ \frac{2}{5} & \frac{1}{5} & -\frac{2}{5}\end{array}\right]$